A slit lamp microscope is used, by an ophthalmologist, for observing an eye (an anterior eye part) of an examinee.
A conventional slit lamp microscope will be explained.
The slit lamp microscope irradiates an eye of an examinee with a slit light from an oblique direction so as to visualize and observe transparent or semi-transparent tissues. The slit lamp microscope includes a slit light optical system for emitting the slit light and a microscope unit.
Generally, a slit light source is provided above a mirror. The slit light emitted downward from the light source is reflected, by the mirror, to irradiate the eye of the examinee.
Therefore, a cable for supplying electric power to the light source is usually connected to an upper end part of the slit light optical system (see FIG. 1 of Patent Document 1).
In case of irradiating the eye of the examinee with the slit light only, an irradiation point on the eye is sometimes unknown. In this state, if a picture of the eye is taken, the slit light will be focused on a slit. To solve this problem, a backlight source for illuminating a circumference of the slit light, is provided to the conventional slit lamp microscope.
Patent Document 2 discloses light emitting diodes (LEDs) used as a backlight source. An auxiliary lamp unit including the LEDs is attached to a front end part of a flexible arm.
The flexible arm is attached to a face supporting section, which supports a face of the examinee, and the backlight is emitted from a position above the eye of the examinee.